Diagnostic lift



United States Patent [721' Inventor Jon S-lhktud 3,098,542 7/1963 Wallace 18718.49 sgzgg l vcnlilomla 3,315,763 4/1967 187/854 1211 7 FOREIGN PATENT 221 Filed Sept-3,1968 5 35,929 5/1966 Finland 187/8.4l [45] Patented Nov. 10,1970 1225 362 9H9 G p 187 8 54 [73] Auignee WeeternManuhctnrlngCompany 52'793 7 1933 lummdmp orwayuw Primary Examiner- Harvey C. Homsby Attorney- Lothrop and West [54] DIAGNOSTIC Lll'l 4 Claims, 12 Drawing Figs [52] US. Cl. l87/8.54,

I 187/849, 187/841, 187/17 7 [51] lnt.CI........ B66f7/00 S C A vehide lift fo use on a fl includes lifti rams adapted to ris above the floor and each having a T crosshead at the top for carrying the vehicle wheels. A support bar overlies the crosshead and can be separately supported [56] Remnm cited from the floor level by a strut alongside the ram. Releasable UNITED STATES PATENTS latches connect the crosshead to the strut and support the strut at the floor.

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Pa ented N0 10, 1970 I 3,539,036

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DIAGNOSTIC LIFT The servicing of road vehicles, particularly passenger automobiles, requires the lifting of the vehicle from the floor sufficiently so that the under portions of the vehicle can be inspected and worked on. A lift for this purpose is shown in .l. H. I-Ialstead U.S. Pat. No. 2,949,978 of Aug. 23, 1960. Recently it has become of interest to'make further inspections of the vehicle and to afford better ways of testing and working on the vehicle. This includes the desirability of supporting the vehicle so that the front wheels can be checked for steering alignment and for manipulation of the steering linkage and so that the rear wheels can be operated under power. Further, it is desirable to support the chassis in such a way that any or all of the wheels can be detached and remounted; for example, in changing tires, balancing wheels, inspecting and working on thebrakes and performing similar services. Engine and drive train testing is desirable and for some purposes can be accomplished with the drive wheels (usually the rear wheels) free to 1 rotate but for other purposes should be done with the drive wheels on a traction dynamometer, preferably one available easily to the lift. A lift of assistance in carrying out the extensive checking, operating and repairing operations now of interest is referred to as a diagnostic lift.

It is therefore an object of my invention to provide an improved diagnostic lift.

Another object of my invention is to provide a diagnostic lift effective to handle a vehicle in such a fashion that the wheels have no vehicle load upon them.

Another objector the invention is to provide a diagnostic lift in which the liftjsat all times maintained in a safe condi-- tion against accidental lowering.

Another object of the invention is to provide a diagnostic lift in which the forward end and the rearward end of the vehicle can be independently lifted and lowered.

Another object of the invention is to provide a diagnostic lift utilizinga circular cylindrical lift ram but in which the lift ram cannot be rotated about the ram axis.

Another object of the invention is toprovide a diagnostic lift which can readily be operated without special or elaborate instruction.

Another object of the invention is to provide a diagnostic lift which is a substantial improvement over lifts now available.

A further object of may invention is to provide a diagnostic lift having a special latch mechanismfor holding the weight supporting members.

A further object of my invention is to provide a lift having means for supportinga vehicle by the vehicle wheels or by the vehicle frame or both.

j A further object of my invention is to provide a lift having means for supporting a vehicle with all of the wheels at a predetermined distance fromtheground.

Other objects together with the foregoing are attained in the embodiment: of the invention described in the accompanying descriptionand illustrated in the accompanying drawings, in which:

FIG. I is a side elevation of a diagnostic lift constructed pursuant tothe invention,certainportions of the surroundings being broken away to disclose the lift construction, and some parts being diagrammatically shown;

FIG. 2 is a plan of the lift structure shown in FIG. 1;

FIG. 3 is a front end elevationof the structure shown in FIG. 2 with certain portionsbeing broken away to reduce the size of the figure;

FIG. 4 is a view similar to FIG. 3 and showing the parts in onediagnosticposition;

FIG. 5 ,isa view similar to FIG. 4 but showingthe parts in another diagnosticposition;

FIG. 6 is a detail in cross section of one of the front latching mechanisms, theview beingtaken on the lines 6-6 of FIG. 4;

FIG. 7 is a detaillof another latching mechanism, the plane of which is indicated by theline 7-7 of FIG. 4;

FIG. 8is a view similarto FIG. 6 but showing the latching mechanism in a different position;

FIG. 9 is a view similar to FIG. 6 but showing the latching mechanism in position with the lift lowered;

FIG. 10 is a detail in cross section of one of the rear latching mechanisms in latching position;

FIG. 11 is a view similar to FIG. 10 but showing the rear latching mechanism in a different position; and

FIG. 12 is a view similar to FIG. 10 but showing the rear latching mechanism in positionwith the lift lowered.

The diagnostic lift pursuant to the invention is primarily for use with road vehicles such as passenger automobiles, although it can well be used for other wheeled vehicles as well. The form shown herein is the usual commercial installation for use with passenger vehicles. The diagnostic lift is preferably installed in and on the ground 6, customarily finished to provide a floor 7 of concrete or the like. The term floor is utilized herein to refer generally to any supporting medium, whether earth, concrete, steel or the like, which serves as the base or foundation for the lift.

The lift includes a pairof physically separate lifting rams 8 and 9. These are substantially identical and are disposed at a convenient distance apart in the ground 6. The space between the front ram 8 and the rear ram 9 is preferably utilized for the installation of a traction dynamometer 10. This is a standard device and so is not illustrated in detail. It is in position to be engaged by the vehicle wheels when the vehicle is properly located. The rear lifting ram 9 includes an outer cylinder 11 concentric with a vertical axis 12. Within the cylinder is reciprocably disposed a piston or plunger 13 adapted to move along the axis 12 from a nested position within the cylinder to an extended position considerably above the floor 7. At the upper end, the piston 13 carries a transversely extending cross head 14 in the nature of a heavy metal plate. At its ends, the crosshead supports a pair of parallel, wheel-receiving channels 16 and 17 havingramps 18 and 19 at their ends to facilitate the driving of vehicle wheels thereover. Sometimes the ramps 18 and 19 are movable members but for simplicity herein these are disclosed as stationary as movable ramps are 'well known in the art. 3

Ina similar fashion there is afforded in the cylinder 20 of th front ram 8 a piston or plunger 21- designed to reciprocate along a vertical axis 22. At its upper end the piston 21 carries a crosshead 23 supporting a pair of wheel channels 24 and 26, each of which has a rear ramp 27 and a front ramp 28. In the present instance, the rams 8 and 9 are operated by a combination of hydraulic and pneumatic means, as diagrammatically shown in FIG. 1. Conduits 31 and 32 from the cylinders 20 and 11 extend to control valves 33 and 34, having individual but closely spaced actuating handles 36 and 38. The handles are arranged so that they can both be simultaneously manipulated by one hand of the user or can be individually moved, if desired. The valves 33 and 34 join to a pipe 39 leading to a point near the bottom of an accumulator or storage tank 41 buried in the ground 6 (in most installations) and adapted to contain a body 42 of oil or comparable hydraulic fluid.

Connected to the top of the tank 41 is an air pipe 43 rising to an air control valve 44 having a manual operator 46 thereon. The valve 44 has three positions. In one position air under pressure from a duct 47 is directed into the pipe 43 and to the tank 41, which'is thus put under air pressure. An intermediate position of the handle 46 closes off the pipe 43 and maintains air confined within the tank 41. In the third position of the handle 46 air from the tank 41 and the pipe 43 is released to the atmosphere through an exhaust muffler 49. By appropriately manipulating the handle 46, the user can place the tank 41 under superatmospheric pressure, under atmospheric pressure or can leave the tank pressure in static condition.

Whenoil within the tank is subjected to superatmospheric pressure, proper operation of the handles 36 and 38. puts either one or both of the pistons 13 and 21 under lifting pressure or under holding-pressure or under nearly atmospheric pressure so as to lower by gravity. In this fashion the rear ram 9 can be lifted and lowered independently, the front ram 8 can be lifted and lowered independently, or, as is normally the case in most applications, both of the rams can be raised or lowered substantially simultaneously or can be held at any desired elevation.

For diagnostic work, particularly front wheel alignment and checking, the crosshead 23 of the forward ram 8 is preferably provided with rotary tables 56 each mounted to revolve about its own axis 57 centrally of the channel 24 or 26. Removable holding keys 58 (FIGS. 1 and 2) are normally engaged with the rotary tables 56 and the subjacent crosshead so that the tables are held from rotation. However, when a vehicle steering wheel is resting on the table, the key 58 can be removed and then the wheel steering motion is accompanied by rotation of the table 56 about the axis 57. This rotational movement can be measured or otherwise used for diagnostic and repair purposes. The rotary table mechanism is a commercially available feature and is therefore not further described.

Pursuant to the present invention, either the rear ram 9 or the front ram 8 may be supplemented by an additional holding and supporting mechanism. Herein both rams 8 and 9 are so equipped. The mechanisms are virtual duplicates so the description of one applies also to the other, except when noted. Disposed to overlie the subjacent ram crosshead 23, for example, is a support bar 61. This is a crossmember of relatively heavy metal having in cross section, as shown in FIG. 6, a T-shaped configuration. The support bar 61 is of lesser length than the crosshead 23 and in most designs is also of lesser width. Although the support bar under some circumstances simply rests on the crosshead, it is provided with a separate support mechanism of its own.

Adjacent one end the support bar 61 is joined to a vertical strut 63 and near the other end is joined to a similar vertical strut 64. The struts preferably are hollow or are tubular cylinders fastened at their upper ends to the support bar and depend through openings 65 (FIG. in the crosshead 23 to lie within casings 66 buried in the ground 6 below the floor 7. Although sometimes but one strut is utilized, it is preferred to provide two, as shown, and to locate them with their own axes parallel to the axis of the ram and to dispose them symmetrically on opposite sides of the ram. Being eccentrically located, the strut or struts keep the ram pistons from rotating.

There is provided on one or preferably both the front and rear support bars at least one and usually two flanged slides 71 and 72 of standard construction as shown in the above-noted patent. The slides are movable transversely of a vehicle and along the length of the support bar by manual displacement. Each of the slides'71 and 72 is like the other and carries a rotatable arm 73 having a central pivot 74 on the slide. At its end or near its end the arm 73 has one or more pivoted tip-up supports 76. The tip-up support can lie flat over the arm 73 or can be swung into a vertical position, as shown in FIG. 4, to support a vehicle part at a substantial distance above the support bar.

When the rear ram 9, as shown, is provided with the same mechanism as the front ram, there are four tip-up supports 76 that can be variously moved and adjusted for engagement with up to four parts of the chassis or frame ofa vehicle on the lift.

Means are provided for releasably relating each support bar 61 and its subjacent crosshead 14 or 23. The front and rear mechanisms are substantially the same except for the latching devices. As particularly shown in FIGS. 6, 8 and 9, each of the front struts 63 and 64 is provided with a swinging link 78 movable about a cross pivot pin 79 seated in the tube between one position in which an extension 81 of the link is contained entirely within the hollow strut (FIG. 6) and another position (FIG. 8) in which the extension 81 projects through an opening 82 in the strut wall.

The link 78 is unstable and is so balanced that in the unlatched position its center line 83 lies to the left (FIG. 6) of the vertical and gravity tends to hold the link in unlatched position. When the link is reached through an access hole 84 in the strut 64 and is pressed inwardly, its center line 83 moves a distance A past vertical until a stop 85 abuts the inside wall of the strut where it tends to stay by gravity.

When the support bar 61 is adjacent the crosshead and the link 78 has its extension 81 projected, the link acts as a detent or latch and lies just under the lower surface of the crosshead and in its path of separating movement. Thus, the extended link acts to prevent any substantial separating movement of the support bar with respect to the crosshead. There can be some small movement or play between them, largely for manufacturing and assembling reasons and exaggerated in the drawings for clarity, but in effect the support bar and crosshead are unitary when the link 78 is in its projected position. When the extension 81 lies within the interior of the strut tube as shown in FIG. 6, then the support bar and crosshead can move quite independently.

When, as shown in FIG. 9, the strut 64 descends into the casing 66 in the floor, the cammed or inclined lower edge of the extension 81 rides over the rim of the casing and throws the link 78 over center by an amount B. The link stays there until manually pressed away from the opening 84, as previously described.

Releasable means are provided for supporting the struts on the floor 7 or the adjacent lift mechanism buried in the floor. These means are of the type shown in J. H. Halstead US. Pat. No. 2,956,643 of Oct. 18, 1960. As particularly shown in FIG. 7, each strut in one or preferably several vertically spaced places is provided with apertures 86 and 87 through which may extend a safety lever 88 mounted on a pivot pin 89 spanning the interior of the strut tube. The shape of the lever 88 provides an overbalancing weight 91 at one end and a projection 92 at the other end. In one rotated position about the pin 89 the safety lever is entirely contained with the strut so that the strut can move upwardly and downwardly without interference. However, when the lever 88 is revolved into the horizontal position shown in FIG. 7, then when the strut lowers, the lever contacts the adjacent top of the casing 66 or the floor. The lever 88 serves as a stop to prevent further lowering movement of the strut. Since there are preferably several such levers, the strut can be stopped and is firmly supported in any of several locations at different heights.

In addition to the safety levers 88 the rear struts 63 and 64 have latch links but these differ somewhat from the links 78 in the front struts. As particularly shown in FIGS. 10, 11 and 12, each of the rear struts, say 64, has a link 93 at its lower end mounted on a cross pin 94 seated in the strut walls. At its upper end the link 93 has an extension 96 designed to project through an opening 97 in the strut wall and notched to abut the strut wall as a stop. In this position the link underlies and serves as a latch for and is held over by the crosshead 23, being also urged by gravity into the projecting position since the center line of the link is beyond vertical by an amount C. When the link 93 is pressed inwardly after the load of the crosshead 23 has been relieved and the extension 96 is moved into the strut, the link is overbalanced and moves into a position with its center line past vertical by an amount D (FIG. 11). In this position, a wing 98 projects through an opening 99 in the strut wall. The wing is upwardly rounded and the crosshead 23 is spaced far enough from the strut so that the crosshead can descend with respect to the strut without displacing the link over center. Yet, when the strut descends into the casing 66, as shown in FIG. 12, the wing 98 cams against the casing edge, the link is cammed over center and the extension 96 rides against the inside of the casing with a displacement E. When the casing rises again, the link 93 falls outwardly into its FIG. 10 position ready to latch the crosshead 23.

In the operation of this structure the user drives a vehicle over the lift when the lift is in its lowermost position. If desired, the vehicle can be initially positioned so that the driving wheels engage the dynamometer 10 and the engine and drive train can be tested. Then the vehicle is positioned in a location for lifting. The handle 46 is then actuated to put the reservoir or accumulator tank 41 under pressure. Following that the handles 36 and 38 are simultaneously or individually actuated to raise the pistons 13 and 21 out of their cylinders. The crossheads 23 are thus raised and raise the channels 24 .ticularly desiredto relieve the load on the tires and wheels and the adjacent suspension mechanism. For that reason the tip-up supports 76 are set upright and the links 78 and 93 are manually pressed into the interior of the struts. Then the levers 36 and 38 are reversed to lower the pistons 13 and 21. This lowers the crossheads substantially to the floor, as shown in H6. 5. Since the safety levers 88 are extended and support the struts 63 and 64,the support bars 61 cannot lower. As the vehicle wheels lower with the rams, the vehicle frame or chassis portions come-into contact with the upright tip-up supports 76. The major weight of the vehicle is thus transferred to and directly carried by the struts 63 and 64 at both ends of the lift. This leaves the wheels and attendant gear free to lower as far as they can during the remaining descent of the rams. The wheels can hang freely in air above the channels 16 and 17, as shown in FIG. 5, or can bear whatever portion of the total load the operator desires, depending upon the amount the rams are lowered.

In the free position of the vehicle wheels, as shown in FIG. 5, the wheels can be rotated or otherwise manipulated and the adjacent portions of the chassis are free for test, work, inspection, replacement or the like.

At the conclusion of the diagnostic or repair operations the rams are again raised until such time as they pass upwardly camming over the levers 78 and-93 and again are in an upper position. lf the forward support bar 61 is to be latched for lowering movement, the links 78 are manually projected. The

rearward links ,93 automatically fall into latching position. The channels 16 and 17 again bear the vehicle load that'previously was on the support bars and struts 63 and 64. When the crossheads attain an upper position and bear the weight of the support bars and of the vehicle again, a slight further lifl permits the safety levers to be rotated into their retracted position. The reversal of the levers 38 and 36 lowers the pair of rams with the crossheads and support bars descending together until the vehicle is resting near the floor. It can then be driven off of the support channels and the diagnostic lift is available for subsequent use.

lclaim:

l. A diagnostic lift for use on a floor and with a vehicle having a longitudinal axis comprising alifting ram adapted to rise above said floor along a vertical axis substantially intercepting said longitudinal'axis, a horizontal crosshead extending transversely of said longitudinal axis and centrally supported on said ram, means including a pairof longitudinally disposed wheel receiving channels horizontally mounted on the opposite ends of said crosshead for engaging wheels of a vehicle on said lift, a horizontal support bar extending transversely of said longitudinal axis between said channels and overlying and normally supported by said crosshead, said crosshead having an opening therethrough, means on said support bar for engaging the. frame of said vehicle, at least one vertical strut on one side of said lifting ram extending slidably through said opening and rigidly fixed on and depending from said support bar downwardly below said floor, and means on said strut movable from a position within said strut to a position projecting from said strut for supporting said strut from the floor level.

2. A diagnostic lift as in claim 1 including means on said strut movableyfrom a position within said strut to a position projecting from said strut in substantial engagement with the underside of said crosshead for releasably interconnecting said crosshead and said strut.

3. A diagnostic lift as in claim 1 in which there are two of said struts depending from said support bar each adjacent one of the ends thereof and disposed on opposite sides of said lifting ram.

4. A diagnostic lift as in claim 1 including a casing extending below said floor in position to receive said strut and terminating substantially at the level of said floor for engagement by said supporting means in projecting position. 

